1. Field of the Invention
This invention relates to a tool changing machine of a machine tool, more particularly to a tool changing machine provided with a tool magazine with a plurality of tool cartridges, having tool sockets.
2. Description of the Prior Art
A machine tool with an automatic tool changing machine enables continuous, diverse machining of a workpiece by the selective use of various tools accommodated in the tool magazine.
A known tool changing machine comprises a tool magazine, which accommodates a plurality of tools and selectively brings the tools to a tool changing station, and a tool transferring device, which exchanges an indexed tool for a tool which is mounted on a spindle of the machine tool.
A conventional tool magazine is usually disc-shaped with tool sockets on the periphery of the disc or chain-like with tool sockets connected to each other in a chain fashion in these conventional tool magazine, however, to increase the number of the tools accommodated in the magazines, it is necessary to make the magazine larger, increasing the size of the tool changing machine. This in turn increases the necessary installation space of conventional tool changing machines.
There is also known a drum-type tool magazine which has a cylindrical body which is provided, on its outer periphery, with a plurality of cartridges having tool sockets, as disclosed in, for example, U.S. Pat. No. 3,715,801. Even this type of cartridge, however, has the drawbacks of difficult tool change and complex construction. A plane planar tool cartridge which has a plurality of tool sockets in a plane is disclosed in Japanese Unexamined Utility Model Publication (Kokai) No. 49-21672. This planar cartridge, however, needs a large space for the sliding movement of the tool magazine in the plane.
To feed a large number of tools without increasing the magazine size, it is known to convey to the tool magazine additional tools stored, for example, in a separate tool storage and to exchange those additional tools for the tools in the tool magazine.
An example of such a device comprises a carriage which moves between the tool storage and the machine tool with a plurality of additional tools and a means for individually exchanging the additional tools for the tools in the tool magazine, as disclosed, for example, in Japanese Examined Patent Publication (Kokoku) No. 53-21543. However, individual exchange of tools takes a long time and, accordingly, is inefficient.
Another example of such a device is disclosed in Japanese Unexamined Patent Publication (Kokai) No. 55-31576, in which the device has a carriage similar to the above and an auxiliary tool magazine which is exchanged with the main tool magazine of the tool changing machine. In this device, however, the entire tool magazine of the tool changing machine must be exchanged even when only some different tools are required. Further, in this device, replacement of a single broken or worn tool necessitates replacement of the entire tool magazine.